Truline turns your phone into a set of measuring instruments: a bubble level, surface level, on-screen ruler, protractor, compass, angle finder, vibration meter and flashlight. It uses the sensors already inside your phone, works fully offline and asks for no permissions.

EIGHT INSTRUMENTS

• Bubble Level – check shelves, pictures and frames. Plumb mode shows how far a wall, post or door frame leans. A short tick confirms the moment it is level.
• Surface Level – a round bullseye level for tables, appliances and floors, with X and Y readings.
• Ruler – measure small objects directly on the screen in centimeters or inches. Calibrate once with a standard bank card for better accuracy.
• Protractor – drag two arms to measure any angle, with radians, complement and supplement.
• Compass – heading in degrees with a clear cardinal direction and an accuracy indicator.
• Angle Finder – measure the incline of a ramp, roof or stair along the side or bottom edge of the phone, with slope percent, rise per run and grade. Hold the reading or set a relative zero.
• Vibration Meter – live vibration in m/s² with peak, average and a scrolling graph, for washing machines, fans or a wobbly table.
• Flashlight – rear light with an SOS pattern, automatic switch-off after 10 minutes, and a white screen light for phones without a flash.

MADE FOR REAL USE

• Two-position calibration for the level sensor gives you a true zero.
• Hold freezes any reading so you can check it after moving the phone.
• Save readings with a label, like "Kitchen shelf" or "Garage ramp", and copy them later.
• Show angles in degrees or percent slope, lengths in metric or imperial.
• A raised level button in the bottom bar opens the bubble level from anywhere.
• Step-by-step guides for every instrument.
• Clean light design with large numbers that are easy to read.

PRIVATE BY DESIGN

• No account and no sign-in.
• No ads and no in-app purchases.
• No Android permissions requested.
• No internet connection used – saved readings, calibration and settings stay on your device.

GOOD TO KNOW

Accuracy depends on your phone's sensors and screen. Most phones read within 0.1–0.5° after calibration. The compass is affected by magnets and metal nearby. For work where precision matters for safety, use a professional tool.

Truline is a small, focused utility. If an instrument you need is missing, tell us through the developer contact on this page.